Symlink following in thClaws allows writes outside the workspace
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Passive
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- —
- Confidentiality · integrity · availability
- None · Low · Low
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA.
Summary
thClaws through 0.141.0 contains a link-following flaw (CWE-59) in the post_inputs handler of the POST /v1/inputs endpoint. The handler follows symlinks, so writes can reach files outside the workspace. A remote attacker with no privileges who plants a symlink under the inputs/ prefix can make later authenticated uploads write or truncate files outside the workspace with daemon privileges.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
Description from the CNA
thClaws through 0.141.0 contains a link-following vulnerability in the post_inputs handler of the v1 API POST /v1/inputs endpoint that allows writes outside the workspace by following symlinks. Attackers who plant a symlink under the allowed inputs/ prefix can cause later authenticated uploads to write or truncate files outside the workspace with daemon privileges.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
The sources list no fixed version for thClaws.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
Timeline
- 2026-10-11 Threatist record created from CVE-2026-108839
- 2026-10-11 Alias added: GHSA-8c39-3r7m-gwc4
- 2026-10-18 CISA SSVC decision points changed
References
Sources
- CVE-2026-108839 · CVE Program
- CVE-2026-108839 · NVD
- FIRST EPSS
- GHSA-8c39-3r7m-gwc4 · GitHub Advisory Database · CC BY 4.0
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